1. Field of the Invention
This invention relates in general rail to cars and more particularly to side sheets for a hopper and bulk container rail car.
2. Summary of the Prior Art
Hopper and bulk container cars have long been used to transport granular material, such as, for example, plastic pellets, cement, grain, wood chips and the like. A hopper and bulk container car is provided with a hopper body formed on its sides by a pair of parallel side walls, which may be covered or open. The lading being transported is generally discharged through chutes located beneath the car. In the past, the side walls of a hopper car have been constructed with a plurality of vertical sheets which are vertically welded to each other. In addition, the welded side walls are welded at their top to the hopper top chord and at their bottom to the side sill disposed on opposite sides of the car body. This unit is then welded to the car structure. The employment of multiple side sheets, such as 6 or 8 in number along each side of the car, requires an extensive use of welds to satisfactorily attach the side sheets to the car body and to render the structure adequately strong to resist loading and stresses normally associated with operation of a rail car. The need for such extensive welding of side sheets is time consuming and labor intensive during manufacture of the rail car and adds significant weight to the finished rail car.
In addition, known multiple vertical side sheets produce unsightly imperfections on the exterior of the wall which are referred to as xe2x80x9coil canning.xe2x80x9d In the past, hopper and bulk container cars have been provided with a plurality of vertical side sheets because of the difficulty in forming elongated horizontal sheets, particularly extending the length of the body as the wall structure. Long sheets of material, such as length wise side sheets, are preferably formed from rolls of coiled metal. As the coiled metal is unreeled, however, the sheets inherently possess a camber whereby the sheets do not come off the coil with a straight configuration and create deviations unsuitable for use on a rail car. Moreover, elongated sheets have heretofore not possessed the desirable rigidity for use as a side wall structure. Accordingly, it is desirable in the rail industry to provide elongated side sheets producing a superior side wall structure having less weight, a better appearance and enhanced rigidity.
It is therefore an objective of the invention to provide improved side sheets for a hopper and bulk container car in which the side sheets on each side of the car extend horizontally along the length of the hopper compartment. In a preferred embodiment, the invention herein disclosed utilizes a pair of side sheets horizontally arranged along the side of the car and which are welded in securement as a unitary wall structure. The side sheets of the invention allow the problem of coil camber to be controlled by having a plurality of shallow ribs formed in horizontal orientation along their length. The shallow ribs insure a straighter side sheet because the edges are controlled so that a straighter structure is obtained. The use of such horizontal ribs not only eliminates the problem of coil camber, but provides strengthening rigidity to the structure of the side sheets for a stronger hopper car body. The use of horizontally arranged side sheets, such as two in number, greatly eliminates the number of welds which are necessary during manufacture of the side walls of the hopper bulk container car. The reduction in welds permits a more economical fabrication of the rail car with lighter weight side walls. Because the side sheets have straighter edges due to the presence of the horizontal ribs, the side sheets of the invention are readily attachable to the top chord, the side sill, and to each other along a horizontal seam. The side sheets in accordance with the invention are preferably formed by a cold forming process to achieve the foregoing improved results.